The present invention relates to a novel leukemic cell growth inhibiting agent or, more particularly, to a leukemic cell growth inhibiting method by using a medicament of which the effective ingredient is a methylsulfinylalkyl isothiocyanate derived from certain plants belonging to the family of Cruciferae. The invention further relates to a therapeutic method for leukemia.
As is known, leukemia is a disease caused by the autonomic growth of leukocytes in the bone marrow and sometimes called a blood cancer accompanied by anemia, leukocytosis, thrombocytopenia and the like. In addition, it is known that leukemia sometimes leads to formation of secondary infiltration focuses, i.e. metastasis, or secondary hematopoietic focuses in other organs such as the liver, spleen, lymph nodes and the like.
A great variety of compounds are proposed as a therapeutic medicament of leukemia including synthetically prepared compounds, antibiotics and natural substances as well as interferons, interleukins, TNFs (tumor necrosis factors), CSF- (colony-stimulating factors) suppressing substances and the like as bio-technological products. These medicaments have an activity of interacting with the leukemic cells to inhibit growth thereof or to cause necrosis thereof so as to exhibit a therapeutic effect on the leukemia. Necrosis mentioned above to kill cells involves very serious defects that the cell-killing effect extends not only to the diseased cells but also to normal cells therearound and other new diseases are resulted.
Accordingly, it is eagerly desired to develop a novel therapeutic medicament for leukemia which never affects any normal cells acting only on the diseased cells to cause growth inhibition or necrosis thereof.
Several apoptosis-inducing leukemic cell growth inhibitors were discovered as a therapeutic medicament for leukemia satisfying the above mentioned requirements including lectin proteins extracted from the pulpous flesh of a fungus called yanagimatsutake (Agrocybe cylindracea), lectin proteins separated from the beans of touazuki (Abrus precatorius), hinokitiol extracted from the plants belonging to the family of cypresses and others.
The apoptosis mentioned above is a life phenomenon to avoid the disadvantage caused by persistence of damaged cells which can be repaired with great difficulties, in which such damaged cells are autolytically destroyed along a sequence of programs. Namely, a therapeutic medical means for leukemia could be provided by using such an apoptosis-inducing leukemic cell growth inhibitor since the leukemic cells in the blood alone can be selectively destroyed by autolysis with little influences on normal cells.
It is known that, when the tissue of a plant belonging to the family of Cruciferae is ground, a methylsulfinylalkyl isothiocyanate is formed from the glucosinolate in the tissue. As is reported, some of these isothiocyanate compounds exhibit a suppressing effect against esophageal cancer and proventriculus cancer of rats artificially induced by nitrosamine and the gastric cancer, mammary cancer and lung cancer of human suspectedly induced by 7,12-dimethylbenz[a]anthracene or benzo[a]pyrene but no information is available on the activity of these isothiocyanate compounds against leukemic cells.
The present invention accordingly has an object to provide a novel therapeutic method for growth inhibition of leukemic cells by administrating the leukemic patient with a novel apoptosis-inducing leukemic cell growth inhibitor which is a compound obtained from a raw material of good availability.
Thus, the growth inhibiting method against leukemic cells provided by the present invention comprises: bringing the leukemic cells into contact with a leukemic cell growth inhibitor which is a methylsulfinylalkyl isothiocyanate represented by the general formula
CH3xe2x80x94SOxe2x80x94(CH2)nxe2x80x94Nxe2x95x90Cxe2x95x90S,xe2x80x83xe2x80x83(I)
in which the subscript n is a positive integer in the range from 2 to 8.